Nepedia
Back to Discover
Fluent Reader
🧬

Humerus

life science Maturity 11-13 Next article →

The humerus is a long bone in the arm.

Humerus ant (mirroed)
Humerus ant (mirroed)

It runs from the shoulder down to the elbow. This bone connects the scapula, which is the shoulder bone, to the lower arm. The lower arm contains two bones called the radius and the ulna.

Humerus-Head
Humerus-Head

The humerus is important because it helps the arm move. It provides a strong structure for many muscles to attach to. Understanding this bone helps us see how our arms work.

The bone has three main sections. The top part is called the proximal extremity. It has a rounded head that fits into the glenoid cavity of the scapula.

Neck-of-Humerus
Neck-of-Humerus

This connection creates the glenohumeral joint, also known as the shoulder joint. Below the head is the anatomical neck. Further down, there is a narrow area called the surgical neck. This area is a common place for a fracture to happen.

Capitulum-and-trochlea
Capitulum-and-trochlea

The middle part of the bone is the shaft. It is shaped like a cylinder or a tube.

Anterior-view-of-the-humerus-showing-borders-and-surfaces
Anterior-view-of-the-humerus-showing-borders-and-surfaces

The shaft has different surfaces and borders. One part is the deltoid tuberosity, which is a rough bump. This is where the deltoid muscle attaches to the bone.

Deltoid-Tuberosity
Deltoid-Tuberosity

There is also a spiral groove on the back side. This groove carries the radial nerve and some blood vessels.

Radial-groove-continuing-as-lateral-border-of-shaft
Radial-groove-continuing-as-lateral-border-of-shaft

A small hole called the nutrient foramen lets blood vessels enter the bone.

The bottom part is the distal extremity. It is near the elbow and is somewhat flattened.

This section has two bumps called the medial and lateral epicondyles. It also has parts called the trochlea and the capitulum. The capitulum is a smooth, rounded part that connects to the radius.

Capitulum-and-trochlea
Capitulum-and-trochlea

There are also three hollow areas called fossae. These include the radial fossa, the coronoid fossa, and the olecranon fossa.

Olecranon-fossa
Olecranon-fossa

These hollows allow the bones of the arm to move during flexion.

Many muscles use the humerus as an anchor point. The greater tubercle is a large bump on the top.

Greater-Tubercle-of-Right-Humerus
Greater-Tubercle-of-Right-Humerus

It is a place where muscles like the supraspinatus attach. The lesser tubercle is a smaller bump nearby.

Lesser-Tubercle-of-Right-Humerus
Lesser-Tubercle-of-Right-Humerus

The bicipital groove is a deep path between these two bumps. This groove holds the long tendon of the biceps brachii muscle.

Bicipital-groove
Bicipital-groove

By acting as a base, the humerus lets us lift and move our arms.

377 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (28)
File:Humerus-Head.gif
Humerus-Head.gif
File:Neck-of-Humerus.jpg
Neck-of-Humerus.jpg
File:Greater-Tubercle-of-Right-Humerus.jpg
Greater-Tubercle-of-Right-Humerus.jpg
File:Attachments-of-greater-tubercle.jpg
Attachments-of-greater-tubercle.jpg
File:Lesser-Tubercle-of-Right-Humerus.jpg
Lesser-Tubercle-of-Right-Humerus.jpg
File:Insertion-of-subscapularis-muscle.jpg
Insertion-of-subscapularis-muscle.jpg
File:Bicipital-groove.jpg
Bicipital-groove.jpg
File:Anterior-view-of-the-humerus-showing-borders-and-surfaces.jpg
Anterior-view-of-the-humerus-showing-borde...
File:Posterior-view-of-the-humerus-showing-borders-and-surfaces.jpg
Posterior-view-of-the-humerus-showing-bord...
File:Deltoid-Tuberosity.jpg
Deltoid-Tuberosity.jpg
File:Radial-groove-continuing-as-lateral-border-of-shaft.jpg
Radial-groove-continuing-as-lateral-border...
File:Nutrient-Foramen.jpg
Nutrient-Foramen.jpg

+ 16 more

More to explore

✨ What else?

Related topics you might enjoy

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.